1. Field of the Invention
The present invention relates to radio frequency identification (RFID) and, more particularly, to a method for switching an antenna, a device for switching an antenna, a system for switching an antenna and a method for addressing antennae in an RFID system, and it further relates to an antenna and an antenna system based on this device for switching the antenna.
2. Description of the Related Art
Radio frequency identification (RFID) technology is a non-contact automatic identification technology, commonly referred to as an electronic tag, which automatically identifies a target object and obtains related data via radio-frequency signals, and the identification operation does not need manual intervention, so it is capable of operating in various harsh environments. RFID technology can identify an item moving at high speed and can identify a plurality of tags simultaneously with rapid and convenient operation.
An RFID system is a wireless system, which is used for controlling, detecting and tracking items, and where the system comprises the following elementary components:
(i). a tag, which is composed of a tag antenna and a chip and is attached to an item to be controlled, detected or tracked, in which case there are generally a plurality of tags included in an RFID system, with each tag having a unique electronic code for uniquely marking the object being controlled, detected or tracked, and the tag can also be referred to herein as a responder;(ii). a reader, which is used for reading/writing the information stored in the tag and can be hand-held or fixed, in which case there is generally one reader included in an RFID system, which reader reads the information stored in each tag (sometimes it can even write the tag information into a tag) so as to achieve the control, detection or tracking of the item to which a tag is attached, and the reader can also be referred to herein as an interrogator; and(iii). an antenna, which is disposed on the reader and is used for transmitting a radio-frequency signal between each tag and the reader so as to transmit information between the reader and the tag.
RFID technology is a breakthrough technology, and currently it is increasingly applied in fields such as logistics and supply management, production/manufacture and assembling, airport luggage processing, mail, express parcel processing, document tracking, library management, animal identification tags, sports timing, entrance guard control, electronic tickets and/or highway automatic toll etc. In retail enterprises, it is the RFID-based smart shelves deployment schemes that are closest to the practical business of the enterprises and at the same time most widely accepted by the enterprises.
In the RFID-based smart shelves, a user uses a specially designed RFID reader installed on shelves to obtain the information of the goods placed on the shelves, and performs the work in the application level such as logistics tracking, analysis of the passenger flow and the like on this basis. This deployment scheme is also close in its form to the traditional market plot and can be remolded by the current facilities on a certain basis, thereby becoming the most widely selected scheme during the initial stage of the RFID application.
The RFID-based smart shelves system is mainly suitable for the item-level applications, for example, the scenario of a library, a retail store (such as a supermarket, a DVD shop, a shoe shop, a clothes shop or a pharmacy). However, all of these scenarios need a large number of antennae to cover all the interested reading areas, but the requirement for the real-time response is not high. Therefore, the success of the RFID-based smart shelves is greatly dependent on the design scheme for switching the antennae.
Currently, there is an antenna switching scheme for the RFID-based smart shelves in the industry, which scheme is based on a centralized antennae networking structure. Here, a radio frequency (RF) switch and an RF router are introduced therein and the reader is switched to the antenna deployed on each shelf via the RF switch and RF router. However, such a centralized smart shelves deployment scheme is very difficult to network, the wiring facilities are complicated and the costs are very high.